Beyond StereolithographyBeyond Stereolithography

Presented by: Paul Armstrong

ConceptsConcepts

Time CompressionCost effective new product introductionRapid PrototypingRapid ToolingFunctional Plastic and Metal PrototypesMarriage of CAD & RP technology with

crafts-based traditional patternmaking skills

“ “ If everything is under control, If everything is under control, you’re probably not going fast you’re probably not going fast

enough”enough”

Mario Andretti

Why Use Prototypes?Why Use Prototypes?Fit and Function TestingDesign Verification and RefinementMarket Analysis and FundingAid for designing production tooling and

fixtures

Benefits of RPBenefits of RP

Quick production of prototype or modelModel produced from designer’s databaseProvides excellent pattern for:

– Aluminum castings via sand or plaster-mold– Plastic parts in thermoplastic resins or urethanes

Machined Aluminum CastingsMachined Aluminum Castings

Plaster Mold–RPM Precision Air-set Sand Graphite Mold

Benefits of RPM CastingBenefits of RPM Casting

Aluminum, zinc or magnesium parts in 1-5 weeks

Die Cast Prototyping – Simulates die casting for

appearance and physical properties

– Soft tooling allows for ease of geometry modification

– Relatively low cost- Magnitude of ten rule of thumb

Benefits of RPMBenefits of RPM

Can be production process for projects that can’t justify hard tooling

Bridge tooling and tooling insurance Replace lost production tools Excellent surface finishes Accommodates complex geometry with undercuts Thin wall sections with excellent weight to

strength ratio– 0.080” wall typical 0.020” wall possible

CastForm CastForm –– Parts in 1 Week Parts in 1 Week

1 SLS MODEL1 SLS MODEL 1 ALUMINUM CASTING1 ALUMINUM CASTING

Precision Sand CastingPrecision Sand Casting

Benefits of Precision Sand Benefits of Precision Sand CastingCasting

Aluminum cast parts in 2-5 weeksExcellent surface finish and overall casting

appearance compared with other sand processes

Superior metallurgical properties

Cast Parts in 2 weeks via Cast Parts in 2 weeks via RPM or SandRPM or Sand

Day 1: file transfer and interpretation engineering review and prep part for

process Days 1-2: creation of master pattern Days 3-5: creation of foundry tooling Day 6: pour & bake molds Day 7: pour castings Days 8-10:secondary operations and qualify

castings

Benefits of Graphite MoldingBenefits of Graphite Molding

Aluminum, zinc or magnesium parts in 3- 5 weeks

Semi-permanent mold will make hundreds of parts from one tool

Ideal for 100-2000 parts– Short run production– Bridge from prototype process to

production Able to cast spec die-cast alloys: 380,

390– More accurate test results for tensile,

yield, hardness

Tensile Strength- 380 T6Tensile Strength- 380 T6

0

510

1520

2530

3540

4550

356 T6 356 Graphite Die Cast

Tensile in KSI

Rapid Injection Molding using Rapid Injection Molding using Cast ToolingCast Tooling

What is Kirksite?What is Kirksite?

Zinc-aluminum alloy– 94% Zn, 6% AL– 725° F melting point

Castable, machinable, weldableZinc is used to enhance tool lifeKirksite molds have been around for fifty

yearsSLA/RP technology unlocked real potential

Benefits of Rapid Injection Benefits of Rapid Injection MoldingMolding

Prototypes in production thermoplastic resins in a 1-4 weeks– Allows for full functional testing

Relatively low cost tooling made from SLA master Bridge or production tooling

– Molds can run thousands of parts

Cast tooling can be used for many plastic processes

Tooling for Rapid Injection Tooling for Rapid Injection MoldingMolding

Prototyping/ Design Verification/Bridge Tool– Cast Kirksite– Sintered Steel– Machined Aluminum

Production– Cast Kirksite– Machined aluminum– Sintered Steel– Machined Steel

Limitations of Cast ToolingLimitations of Cast Tooling

Tolerancing– Tight tolerance CTF

dimensions can be machined into mold or parts

Cosmetics– Appearance critical

areas can be enhanced thru mold finishing

– Upgrade cooling and ejection

Tool life– Molds can run

thousands of parts depending on material

– Dupilcate tool easily made from master

Materials– Glass filled - insert in

high wear areas– Material temp< 725° F

Cast Tooling vs. Cut ALCast Tooling vs. Cut AL

Cheaper and quickerTooling upgradeable after prototype runComplex 3D geometry

– Compound curves– Angular shapes

Speeds design refinement cycleCTF quality requirement

RIM- Reaction Injection RIM- Reaction Injection MoldingMolding

Polyurethane molded parts in 2-5 weeks Excellent flowability and processing allows for molding of:

– Complex shapes– Soft and sharp detail– Thick and thin sections– Openings, ribs and louvers

Foamed polyurethanes are natural thermal and acoustic insulators

RIM BenefitsRIM Benefits

Low internal mold pressuresLow cost tooling allows for ease of

geometry modificationSuperior cosmetic appearance for visible

componentsSuperb encapsulation capabilityReduction in assembly operations with part

consolidation

When to use RIMWhen to use RIM

Housings, bezels, chassis, bases, doors, speaker enclosures

Visually critical applicationsLarge plastic partsEncapsulation requirementsInsulation requirements

Types of RIM toolingTypes of RIM tooling

Silicone rubber - handful of partsEpoxy resin - up to 100 pcsSpray metal - several hundred pcsCast toolingMachined aluminumMachined steel

Thank You for ComingThank You for Coming

Armstrong Mold Corporation6910 Manlius Center Road

East Syracuse, New York 13057-9597Phone: (315) 437-1517

Email: sales@armstrongmold.com Web: www.armstrongmold.com